The present invention relates to a digital copier having a facsimile transmission and reception capability.
A recent achievement in the imaging art is a digital copier which is the combination of a document reader which digitally reads the image of an original document and laser printer or like page printer which records images page by page with predetermined resolution. This kind of copier has a capability of reproducing images in an edited condition and a capability of processing images themselves as well as a usual copying capability. Further, a digital copier may serve as an output unit of a personal computer or like data processing device for producing hard copies or may even be provided with a communication function to serve as a facsimile terminal.
Two different approaches are known in the art for the transmission of images by a facsimile apparatus. One of them is such that an operator loads original documents on a feed tray, then calls a receive station, then confirms the connection of the line, and then presses a start switch to cause the apparatus to sequentially transmit the images of the documents while reading the documents one by one. The other approach consists in storing image data associated with documents in a SAF memory, then calling a receive station, and then transmitting the image data to the receive station when the line is connected. Which of such two different approaches should be selected is a manner of design, and each of them has both merits and demerits. A drawback with the first-mentioned approach is that when the transmit and receive stations are disconnected during communication due to some trouble on the line, the document has to be read again from the beginning. A drawback with the second-mentioned approach is that it needs a higher cost than the first-mentioned approach because an extra memory, i.e., SAF memory is essential. Nevertheless, in parallel with the development of inexpensive semiconductor memories and the increase in the density and operating rate of hard disks and other magnetic storages, the tendency to use the second-mentioned approach is increasing.
Usually, with any of the two different approaches stated above, documents laid on a feed tray are sequentially transported by a document feeder (DF) so that their image surfaces are moved over and relative to an image reader to be read by the latter. The image reader may be implemented by a .times.1 sensor which is constituted by charge coupled devices (CCD). When the number of documents to be transmitted is n, it is a common practice to read and send the first document first and therefore to so construct the DF as to feed the first document first. Usually, n documents are orderly prepared from the first document to the last or n-th document. The stack of n documents are laid on the feed tray either face up or face down depending upon the orientation of the image reader of the facsimile apparatus. When n documents a loaded face up, the DF feeds the uppermost one of the n documents first while, when they are loaded face down, the DF feeds the lowermost one first. In any case, it is the first document that is fed first. Hence, the SAF memory which implements the second-mentioned approach sequentially stores the first document to the n-th document in this order, and the data stored in the memory are sequentially read out in the order they are stored.
In the description made so far, the order of documents is assumed to be the order they are read and stored in the SAF memory and the order they are transmitted. In the description to follow, since the situation is somewhat different, the order of documents (or image data) are represented by the first page, the second page, . . . , and the n-th page, the order of storage is represented by the first sheet, the second sheet, . . . , and the n-th sheet, and the order of transmission is represented by the first transmission, the second transmission, . . . , and the n-th transmission, except otherwise noted.
In the copiers art, some different types of DFs are known such as a SADF which transports documents one by one, an ADF which accommodates a stack of documents and feeds them one by one, and a RADF which repetitively feeds documents. The following description will concentrate on the ADF by way of example, and the ADF will be referred to as the DF for simplicity. When the DF of a copier sequentially feeds the first page to the last page in this order, the resulting stack of copies on a copy tray has the first page at its bottom and the n-th page at its top. Since the order of copies on the copy tray is opposite to the order of documents, a person has to rearrange the copies in order of page. Implementations available for freeing a person from such manipulation are an inverting mechanism which is installed in a paper transport path of a copier, and a DF construction which feeds the last or n-th page first. Let the system which inverts a paper and the system which transports the n-th page first be called a system A and a system B, respectively. While the system A is capable of inhibiting the inverting mechanism from operating (the inhibition of operation of the inverting mechanism or the lack of such an inverting mechanism will be referred to as a system C for convenience), the system B is incapable of selectively effecting the feed from the first page (called a system D hereinafter) and the feed from the n-th page due to the inherent structure the DF. Although such selective feed may be implemented by furnishing a copier with two different kinds of DFs, this scheme is not impractical.
Assume a copier which adopts the system B which is opposite in principle to the system D, as previously stated. It will be seen that the system B is usable in combination with the system C. In the case that such a copier is a digital copier which converts the image of an original document into an electric signal by CCDs or the like and exposes a photoconductive element imagewise by a laser beam which has been modulated by the electric signal or image signal, the copier will serve as a facsimile apparatus if the image signal is fed to a MODEM in place of laser optics. When this kind of facsimile apparatus adopts the previously stated approach which relies on an SAF memory, the following problem is brought about. Specifically, the DF which is based on the system B feeds the n-th page of n documents first and, therefore, the n-th page is the first sheet which is stored in the SAF memory. As such a feed, read and store procedure is repeated, the (n-1)-th page and the first page of course constitute the second sheet and the n-th sheet, respectively. In the event of transmission, the first sheet is the first transmission with the result that the image data arrive at the receive station in the order of the n-th page, (n-1)-th page, . . . , and the first page. On the other hand, when the DF cannot be used such as when the document is a book, a person opens the DF and manually lays the book on a glass platen to cause it to be read in a so-called cover plate mode. In this case, the book is sequentially read the first page first, i.e., in the opposite order to the DF mode (i.e. system B). So long as the copier is used for a simple copying function, copies are produced in the same order in both of the DF mode and the cover plate mode if the systems A and C are replaced with each other. However, when it comes to a facsimile function, the first sheet stored in the SAF memory is read out as the first page and, conversely to the DF mode, the first transmission is also constituted by the first page. The transmission order which varies depending upon the mode as stated is extremely inconvenient for a receive station which cannot be informed of the mode at all.
Assume that facsimile data arrive at the facsimile apparatus of above-described kind. Usually, facsimile image data are transmitted in the order of the first page, the second page and onward of documents. The image data received are temporarily stored in the SAF memory and, upon completion of the reception, printed out. As regards the system A, the image data may be printed out from the first transmission to the last transmission without disturbing the order of page, i.e., the first page and the n-th page will be respectively positioned at the top and the bottom as at the transmit station. However, the order of page is reversed in the case of the system C, requiring a person at the receive station to rearrange the pages.